Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2009 Dec;2(4):321-8.
doi: 10.1593/tlo.09193.

Elimination of Colon Cancer Stem-Like Cells by the Combination of Curcumin and FOLFOX

Affiliations
Free PMC article

Elimination of Colon Cancer Stem-Like Cells by the Combination of Curcumin and FOLFOX

Yingjie Yu et al. Transl Oncol. .
Free PMC article

Abstract

5-Fluorouracil (5-FU) or 5-FU plus oxaliplatin (FOLFOX) remains the backbone of colorectal cancer chemotherapeutics but with limited success. This could partly be due to the enrichment of cancer stem cells (CSCs) that are resistant to conventional chemotherapy. Therefore, validation of a nontoxic agent that can either cause reversal of chemoresistance or promote the killing of CSCs would be highly desirable. The current study examines whether curcumin, the major active ingredient of turmeric, either alone or together with FOLFOX, would be an effective strategy to eliminate colon CSCs. Exposure of colon cancer HCT-116 or HT-29 cells to FOLFOX that inhibited their growth led to the enrichment of CSC phenotype as evidenced by increased proportion of CD133-, CD44-, and/or CD166-positive cells and epidermal growth factor receptor (EGFR) levels. Treatment of FOLFOX-surviving colon cancer cells with either curcumin alone or together with FOLFOX resulted in a marked reduction in CSCs, as evidenced by the decreased expression of CD44 and CD166 as well as EGFR and by their ability to form anchorage-dependent colonies. They also caused disintegration of colonospheres. Increased expression of EGFR in FOLFOX-surviving cells could be attributed to hypomethylation of the EGFR promoter, whereas an opposite phenomenon was observed when the FOLFOX-surviving cells were treated with curcumin and/or FOLFOX. These changes were accompanied by parallel alterations in the levels of DNA methyltransferase 1. In conclusion, our data suggest that curcumin by itself or together with the conventional chemotherapeutic could be an effective treatment strategy for preventing the emergence of chemoresistant colon cancer cells by reducing/eliminating CSCs.

Figures

Figure 1
Figure 1
Sorting of anti-CD44 antibodies-tagged untreated (control) and FOLFOX-resistant HCT-116 cells by flow cytometry. FOLFOX-resistant HCT-116 cells were generated by exposing HCT-116 to 25 µM 5-FU and 0.625 µM oxaliplatin for 48 to 72 hours and subsequently cultured them in normal medium without the drugs for 4 to 5 days. The cycle was repeated 12 times. The surviving cells were then split and exposed to higher doses of FOLFOX (50 µM 5-FU + 1.25 µM oxaliplatin or 100 µM 5-FU + 2.5 µM oxaliplatin) for 2 to 3 days a week for approximately 4 weeks. The FOLFOX-surviving cells were maintained in normal culture medium containing a low dose of FOLFOX (5 µM 5-FU + 0.125 µM oxaliplatin).
Figure 2
Figure 2
(A) Exposure of HCT-116 cells to FOLFOX (50 µM 5-FU + 1.12 µM oxaliplatin) for 48 and 96 hours inhibits growth but increases the proportion of CD133-positive cells as analyzed by flow cytometry after tagging with anti-CD133 antibodies. (B) Levels of CD44 and CD166 mRNA in HCT-116 cells that survived the continuous exposure of FOLFOX (50 µM 5-FU + 1.12 µM oxaliplatin) for 7 and 9 days. The controls represent the parental cells that were incubated with vehicle only. *P < .01, compared with the corresponding control.
Figure 3
Figure 3
Western blot showing changes in the levels of CD166, CD44, and EGFR in parental (untreated control) and FOLFOX-surviving HCT-116 (wt) cells and CD166 in FOLFOX-surviving p53-/- HCT-116 cells after further incubation with the media, FOLFOX (50 µM 5-FU + 1.12 µM oxaliplatin), curcumin (20 µM), or curcumin + FOLFOX.
Figure 4
Figure 4
(A) Representative photograph showing PCR-amplified methylated human EGFR promoter (103 bp; upper panel) and RT-PCR-generated unmethylated human EGFR (107 bp; middle panel) and β-actin (bottom panel). (B) Histogram of data from densitometric analyses of the bands in panel A, normalized for the corresponding β-actin. (C) Western blot showing changes in the levels of Dnmt1 (DNA 5-cytosine methyltransferase) in parental and FOLFOX-surviving HCT-116 cells that were incubated in the absence (control), or presence of curcumin (20 µM), FOLFOX (50 µM 5-FU + 1.12 µM oxaliplatin), or curcumin + FOLFOX.
Figure 5
Figure 5
Representativephotograph showing anchorage-dependent colony formation by FOLFOX-surviving HCT-116 cells in the absence (control) or presence of FOLFOX (50 µM 5-FU + 1.12 µM oxaliplatin), curcumin (20 µM), or curcumin + FOLFOX.
Figure 6
Figure 6
Representative photograph showing disintegration of colonospheres of HCT-116 (A) and HT-29 (B) cells after incubating with FOLFOX (50 µM 5-FU + 1.12 µM oxaliplatin), curcumin (20 µM), or curcumin + FOLFOX for 5 days. The controls were incubated with the medium only.

Similar articles

See all similar articles

Cited by 84 articles

See all "Cited by" articles

LinkOut - more resources

Feedback